The invention relates to an irradiation device comprising
a high-pressure discharge lamp provided with a translucent lamp vessel, which is sealed in a vacuum-tight manner and through the wall of which current supply conductors extend to a pair of electrodes which are arranged within the lamp vessel and between which a discharge path extends, said lamp vessel being filled with an ionizable gas, and PA0 at least one optical conductor provided with a light entrance window at a first end, said optical conductor being arranged laterally of the discharge path in such a manner that the light entrance window is directed to the discharge path.
Such a device is known from U.S. Pat. No. 4,009,382.
In the known device, the optical conductor and the high-pressure discharge lamp are detachably connected to each other. Although the optical conductor has a comparatively large light entrance window, the discharge path of the discharge lamp has considerably larger dimensions so that, only a small part of the generated radiation is collected by the optical conductor, this is also due to the fact that the dimension of the aperture of the optical conductors is small.
The DE-GM No. 8,313,972 (Helmut Hund KG, 3.11.1983) discloses a device in which due to a complicated construction a larger part of the generated radiation is collected by an optical conductor. In this device, radiation generated by a discharge lamp is converged by a cylindrical lens arranged beside this lamp. On the focal line of the lens a bundle of optical fibers is fanned out, which collects the converged radiation. Due to this fan of optical fibers, the quantity of collected light is enlarged, but this does not result in an increase of the brightness of the light emanating from the bundle.
The known devices have the disadvantage that the optical conductor has to be aligned with respect to the discharge lamp by the user. Furthermore, they have the disadvantage that light losses due to the reflection occur not only at the surface of the light entrance window, but also at the inner and the outer surface of the lamp vessel and, with the use of a lens, at both surfaces of the lens. These losses amount to about 4% per surface.
Devices of the aforementioned kind can be used to generate radiation and to irradiate not readily accessible regions, such as cavities in the human body. For this purpose, use may also be made of lasers cooperating with an optical conductor. Lasers afford the advantage that they have a high brightness. However, they have the disadvantage they are generally operated in a pulsed mode and that their operation requires an expensive and voluminous equipment.
The invention has for its object to provide a device of the kind mentioned in the opening paragraph, which has a very simple construction and is nevertheless capable of emitting continuously a high luminous flux via the optical conductor.